1. Field of the Invention
This invention relates to an image reader that reads an image recorded on a recording material by scanning it using an optical beam, and an image recorder that records an image on a recording material by scanning it using an optical beam modulated on the basis of an image signal. More particularly, this invention relates to an image reader and an image recorder designed in such a way as to make it possible to reduce the influence of flare developing in a reading optical beam and a recording optical beam.
2. Description of the Prior Art
Various types of image reader are already known, wherein a recording material on which images are recorded is scanned by a reading optical beam, and the recorded images are read by photoelectrically detecting emitted light, transmitted light or reflected light from the recording material as a result of scanning. Various types of image recorder are also known, wherein images carried by image signals are recorded on a recording material by scanning a recording optical beam, modulated on the basis of an image signal, over the recording material such as a photosensitive material.
In the above-mentioned image readers, there is a possibility that a part of the reflected light occurring when a recording optical beam enters a predetermined scanning point on a recording material is further reflected by an optical system and reenters the other areas of the recording material outside the predetermined scanning point. In many cases, either emitted light, transmitted light or reflected light caused by such flare phenomena may be detected in conjunction with emitted light, transmitted light or reflected light arising from the scanning point. If this is the case, a resultantly read image may have poor contrast.
In addition, the reading optical beam causes flare before entering the predetermined scanning point on the recording material, and weak flare light occurring as a result of the flare may enter the recording material together with the optical beam while being positioned in the vicinity of the optical beam. Even in such a case, emitted light, transmitted light or reflected light caused by the flare light will appear from areas other than the predetermined scanning point, and hence a similar problem may be encountered.
Such flare phenomena may also occur even in the case of a recording optical beam used in the previously mentioned image recorder. If this is the case, a recorded image may have poor contrast.
Conventionally, various techniques are put forward to reduce the influence of flare phenomena developing in a scanning optical beam. For example in U.S. Pat. No. 4,582,988, an image reader is disclosed which has a light shielding member, with a slot elongated in the direction of primary scanning, positioned on a recording material for reading purposes. The scanning of a reading optical beam and the detection of emitted light are carried out through this slit. Moreover, for example in Japanese Unexamined Patent Publication No. Sho-61(1986)-120573, an image reader is disclosed which is provided with a liquid crystal shutter that absorbs a reading optical beam reflected from a recording material.
By virtue of these techniques, it is possible to attain a reduced influence of flare. However, the technique disclosed in the former patent publication encounters problems such as the impossibility of reducing flare occurring in the direction of primary scanning, complicated alignment between the primary scanning line and the slit, and the difficulty of sufficiently reducing a slit width because of manufacturing technique restrictions. The technique disclosed in the latter patent publication results in a costly system because of the expensive liquid crystal.